Archive for the ‘Climate change’ category

Late autumn–winter precipitation in northeast Turkey

January 27, 2012

Jex et al. published a short paper in Quaternary Research about speleothem-derived reconstruction of late autumn–winter precipitation in Gümüşhane, northeast Turkey. The observation goes back to ~ AD 1500 leading to the first long winter precipitation reconstruction for this region. Please refer to http://dx.doi.org/10.1016/j.yqres.2011.01.005 for more information.

Source: Ansto

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Remarkably extensive glaciation in Turkey near the Pleistocene-Holocene boundary

December 26, 2011

A new paper was published in GSA’s Journal of Geology by Zreda and others in November 2011. This is their media paragraph published in the journal’s web site: “Looking at how climate changed in the geological past can provide a useful perspective for studying modern climate change and for predicting climate changes in the next century. Dr Marek Zreda of the University of Arizona and his colleagues used mountain moraines to reconstruct the former glaciers and to determine climatic changes in Turkey at the beginning of the Holocene, the current interglacial epoch. They found that the glaciers were unusually large for that time, with snow lines lower than today by more than 1400 meters, implying a temperature 9°C lower than modern long-term average temperature. The main glacier melting phase lasted 500 years during which the ice margin retreated at the average rate of 1700 m per century, which is higher than modern gracier retreat rates computed over comparable time. This corresponds to the temperature increase at the rate of 1.4°C per century, which exceeds the global warming trend of the past century, 0.6°C, showing that natural causes can lead to fast and large climate changes, and that the magnitude and the rate of climate change observed in the past century are not unprecedented.” Please see more details and the paper here doi:10.1130/G32097.1

Holocene climate change in central Turkey

December 25, 2011

Last 6000 years climate record from Tecer Lake in central Turkey were published in Holoceneby Kuzucuoğlu et al. According to the mineralogy and grain-size distribution of lake sediments, during the mid-Holocene transition, intense droughts occured at the end of the sixth, fifth and fourth millennia BP. The characteristics of some climatic phases at Tecer seem specific to the location of the sequence which, when compared with other sites in the eastern Mediterranean, may record variations in the extent of different climatic systems. Please refer to doi: 10.1177/0959683610384163

A new tree-ring data from western Anatolia

February 8, 2011

Kose et al. 2011 have published a new data set on May-June precipitation of the Late Holocene obtained from 17 black pine tree-rings. Their study was published in the Journal of Quaternary Research. May–June precipitation reconstructions contain mostly one-year and, less commonly, two-year drought events. The longest consecutive dry period was in between 1925–1928 AD. The driest year was 1887. The wettest years for the entire western Anatolia were determined to be AD 1835, 1876, 1881 and 1901. They claimed that the study provides a better understanding of agricultural drought and management of regional water resources. For more information, please refer to doi:10.1016/j.yqres.2010.12.005

 

Earthquakes cycles recorded in calcite veins

February 8, 2011

Uysal et al. 2011 have published a new study about long term seismic cycles recorded in southwest Anatolian calcite veins. The study appeared in the Journal of Earth and Planetary Science Letters. They conducted high-resolution micro-sampling, high-precision U-series dating and micro- chemical analysis on an extensional vein system in a tectonically active area. U/Th ages of the vein system is in between 23.9±0.2 ka and 11.8±0.2ka. Their study offers an innovative means of constraining the absolute timing of late Quaternary seismic and inter-seismic events in Anatolia, Turkey. For more information, please refer to doi:10.1016/j.epsl.2010.12.039

From Uysal et al. (2011) © 2010 Elsevier

Climate change during and after the LGM in Central Turkey

August 22, 2010

Dogan from Ankara University published a new paper in the Journal of Quaternary International about the fluvial responses of Kizilirmak terraces to Late Quaternary climatic changes. A numerical chronology was established by AMS dating of fluvial sediments and Ar–Ar dating of a basalt sample capping the youngest terrace (Late Pleistocene terrace), indicating that the main incision phase was completed at the end of the LGM (Last Glacial Maximum, ~21,000 years ago). It appears that the major climatic transition from the LGM to the Late Glacial gave rise to aggradation in the fluvial system, and this event seems to be consistent with the timing of the regression phase of pluvial lakes and the termination of paleoglacier advances in the high mountains of Anatolia. doi:10.1016/j.quaint.2009.08.004

Bronze age vegetation in the Middle East

August 22, 2010

by George Perfors

Deckers and Pessin have published a paper in the Quaternary Research about the Bronze age vegetation changes in the Middle Euphrates and Upper Jazirah (Syria and Turkey) based on more than 51,000 charcoal fragments of more than 380 samples from nine Bronze Age sites. Human impacts first took place within the riverine forests, and followed by land clearing within the woodland steppe. Local wood supplies at that time were still available despite the increased deforestation. For details, doi:10.1016/j.yqres.2010.07.007